This invention relates to steam turbines and more particularly to low pressure portions of the steam turbine which have blade discs shrunk on a shaft.
The low pressure stages of steam turbines operate in a wet steam environment and because of the large size of the present day turbines are manufactured with blade discs shrunk on a shaft because the diameter of the rotors are large and they cannot be forged in one piece by present day technology. The high stresses in the discs combined with wet steam enhance the probability of stress corrosion, which may result in cracking of the disc initiating at the bore.